The present invention relates to technology to reduce a working time for a carrier by transmitting and receiving data to and from a manufacturing facility while an unmanned transfer device is stopped before performing a carrier work or while it is moving after performing a carrier work, when the unmanned transfer device and the manufacturing facility transmit and receive data for transferring the carrier by using a wireless data communicating device in an automated material handling system.
Generally, in manufacturing processes of a liquid crystal display device and a semiconductor element, the manufacturing goods are transferred to the manufacturing equipment of each manufacturing process by using an automated material handling system (AMHS), so that the corresponding goods are manufactured according to the manufacturing processes of each manufacturing equipment. Such an automated material handling system utilizes an unmanned transporting device for transferring a carrier of receiving a semiconductor substrate or a liquid crystal substrate to the manufacturing station located on the manufacturing process line and transferring the carrier of again receiving the goods completely processed in the corresponding manufacturing equipment to the next manufacturing equipment.
Depending on the movement method thereof, the unmanned transporting device includes an automated guided vehicle (AGV) for driving through the wheel, a rail guided vehicle (RGV) for driving along the guide rail located at the bottom, and an overhead hoist transport (OHT) for driving a guide rail installed in the ceiling. These unmanned transporting devices are moved to the corresponding manufacturing equipment by using the wheel itself or along the bottom rail or the overhead rail and it carries the carrier onto or carries the carrier out the manufacturing equipment by using an operating arm or a hoist and a hand.
The carrying/carrying out of the carriers is accomplished by the host computers mounted on the unmanned transporting device and the manufacturing equipment under the control of the main controller for controlling the entire manufacturing lines. At this time, since it requires the interlock operation between the unmanned transporting device and the manufacturing equipment during the carrying/carrying out of the carrier, transmission devices of an optical communication mode using an IR (Infrared) are installed on the unmanned transporting device and the manufacturing equipment respectively so as to send and receive the necessary data, thereby smoothly performing the carrying/carrying out of the carriers.
FIG. 1 is a block diagram illustrating a communication system for automated material handling system using a conventional optical communication, FIG. 2 is a diagram illustrating a communication process between a manufacturing equipment and an unmanned transporting device of FIG. 1, FIG. 3 is a diagram illustrating a signal configuration of E84 applied to FIG. 1, FIG. 4 is a diagram illustrating a handoff procedure of E84 necessary to a loading, and FIG. 5 is a diagram illustrating a handoff procedure of E84 necessary to an unloading.
Referring to FIG. 1 and FIG. 2, the unmanned transporting device (10) includes an automated vehicle controller (12) and a first communication unit (11) and the manufacturing equipment (20) includes an equipment controller (22) and a second communication unit (21). At this time, the automated vehicle controller (12) sends and receives the carrier by using a SEMI E84, which is a protocol used in the handoff, or a method similar to it through the first communication unit (11) of the unmanned transporting device (10) and the second communication unit (21) of the manufacturing equipment (20).
That is, when it sends and receives the material (1) between the unmanned transporting device (10) and the manufacturing equipment (20), the first communication unit (11) and the second communication unit (21) send and receive the input and output signals each other according to the operation sequence of the E84, so that the materials are loaded or unloaded.
As shown in FIG. 3, the first communication unit (11) and the second communication unit (21) transmit and receive eight input signals and eight output signals according to the operation sequence of the E84. Also, the first communication unit (11) and the second communication unit (21) perform a handoff function on a load port that is, the loading working and the unloading working through the process shown in FIG. 4 and FIG. 5.
At this time, in order to perform the optical communication between the first communication unit (11) and the second communication unit (21), the optical axis should be collinearly. Accordingly, the loading working or the unloading working shown in FIG. 4 or FIG. 5 should be conducted in a state that the unmanned transporting device (10) stops at the corresponding working position of the manufacturing equipment (20).
For example, in a case that the total time on the loading working or the unloading working takes about 10 seconds, the automated material handling system is operated while the unmanned transporting device (10) stops at the corresponding working position of the manufacturing equipment (20) for at least 10 seconds.
That is, there is a limit to the improvement of the overall operation efficiency of the automated material handling system owing to the stoppage time spent on the work performance of the unmanned transporting device.
In other words, in order to operate the automated material handling system more efficiently, it is necessary to minimize the stoppage time of the unmanned transporting device.